Automatic firearm with gas extraction



Feb. 23, 1932. .L DESTREE 1,846,993

AUTOMATIC FIREARM WITH -GAS EXTRACTION Filed Feb. '7, 1931 Patented Feb. 23, 1932 JOSEPH DESTRE, F BRUSSELS, BELGIUM AUTOMATIC FIREARCMC WITH GAS EXTRACTION Application filed February 7, 1931, Serial No.

This invention relates especially to an automatic firearm with gas extraction, in which the automatic mechanism is driven by a piston which moves in a cylinder in the opposite direction to the motion of the projectile under the action of the gases, called motive gases, which act on one of its sides, whereas the gases, called braking gases act on the opposite side in order to brake the above mentioned motion of the piston.

Until now, the. motive gases Which act in that part of the cylinder which is furthest from the breech-block, were extracted from the barrel by a passage which opened into the latter nearer to the breech-block than the passage by which the braking gases Were admitted into the part of the cylinder nearest to the breech-block. Said passages were therefore necessarily crossed.

This arrangement has the disadvantage of causing complicated tooling and diiicult cleaning of said passages, considerable spacel and serious weight.

This invention has for its obj ect to remove these disadvantages.

To this effect, in a iirearm according to the invention, the passage by which the braking gases are admitted to the cylinder, opens into the barrel of the firearm nearer to the breechblock than the passage by which the motive gases are admitted to the cylinder. Experience has proved that this arrangement allows the firearm to be used, although the braking gases are admitted to the cylinder before the motive gases.

It is evident that the extraction of gas which thus takes place from the barrel before the motive gases act in the cylinder has the effect of reducing the pressure of the motive gases, in so far that the chamber of the cylinder into which the braking gases are admitted is necessarily large, since when out of action the piston is at the end of the cylinder opposite to the end near the breech-block.

In order to lessen the reduction of pressure of the motive gases, the invention provides a small cross section for the passage by which the braking gases pass from the barrel into the cylinder. Thus the amount of gas taken from 514,286, and in Belgium February 24, 1930.

the barrel before the extraction of motive gases is small.

In order to compensate the loss of pressure in the motive gases which occurs in spite of all, owing to said extraction, the invention further provides a larger cross section for the passage by which the motive gases pass from the barrel into the cylinder, than that for the passage by which the braking gases pass.

In order that in spite of the small cross section of the latter passage, the braking gases should still have an eiiicacious action on the piston from the commencement of the movement of the latter under the influence of the motive gases, the invention also provides the arrangement of a device, known in itself, in the braking chamber, to guide the gases towards the piston. In this manner the braking gases act upon the piston by a shock.

This shock action is however compensated, according to the invention, by the simultaneous arrangement in the motive chamber, of a device to direct the gases on the piston.

Finally, in order that, in spite of the small cross section of the passage opening into the braking chamber, the piston be not too much braked in its movement under the influence of the motive gases, it is advantageous to arrange, as known, an opening in the wall of the braking chamber of the cylinder, said opening putting said chamber in communication with the atmosphere.

In order that, in spite of this opening, the pressure of the braking gases be not too much decreased, the invention provides that said opening be outside of the path of the braking gases directed towards the piston by the above mentioned device.

Further details and characteristics of the invention will become apparent in the course of the description of the drawing annexed to this specication, and which shows diagrammatically one embodiment of the invention.

This drawing is a view in longitudinal section of part of firearm according to the invention.

It shows a barrel 2 whose breech-block 2a is actuated automatically by the gases which expel the projectile after the explosion. The inside of the barrel 2 communicates with a cylinder 4 by the passages 5 and 6. In the cylinder 4, a piston 7 is arranged, which by means of a mechanical connexion actuates the breech-block 2a. This connexion is of the known type in which the opening of the breech-block and the ejection of the cartridge case are effected during the first movement of the piston 7 under the influence of the gases which expel the projectile, whereas the placing of a fresh cartridge and the closing of the breech-block are effected after said first movement by the influence of springs such as 8.

To effect the automatic operations as above described the piston 7 must therefore, as Shown, be stationary at the end of the cylinder 4 opposite to the end near the breechblock, in order that under the influence of the gases, it is moved in the direction of the arrow X, i. e.; in the opposite direction to the projectile.

The gases which cause this movement, the so called motive gases, are admitted into the motive chamber 4a on to the side 7a of the piston by the passage G, whereas the gases which brake the movement produced in the direction of the arrow X, the so called braking gases, are admitted into the braking chamber 4b on to the side 7b of the piston, opposite to the side 7a, by the passage 5. This latter opens into the barrel 2 nearer to the breech-block 2a than the passage 6 traversed by the motive gases.

The braking passage 5 has a small cross section. The passage 6 for the motive gases has a larger cross section than that of the braking passage 5.

The braking gases, on entering into the braking chamber 4b are directed towards the side 7b of the piston 7 by means of a projection 4d arranged in said chamber, whereas the motive gases on entering the motive chamber 4a are directed towards the side 7 a of the piston 7 by a projection 4f arranged in the latter chamber.

The braking chamber 45 communicates with the atmosphere by an opening 4g arranged in the wall of said chamber near the projection 4d, but on the opposite side to that where the braking passage 5 opens into the braking chamber. This opening 4g is thus arranged outside of the path followed` by the gases when they are directed towards the side 7b by means of the projection 4d.

It is evident that the invention is not exclusively limited to the shape of the embodiment shown, and that many alterations may be made in the shape and the arrangement of the parts used in its embodiment without exceeding the scope of the following claims.

What I claim is:

l. An automatic firearm, comprising a fixed barrel, a cylinder, a piston in this cylinder, a mechanical connection between the piston and the breech-block for directly connecting these two elements, a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the end of the barrel, a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the breech-block, the last passage opening into the barrel nearer to the breech-block than the first passage, and means for reducing the action of the braking gases relatively to the action of the motive gases.

2. An automatic firearm, comprising a fixed barrel, a cylinder, a piston in this cylinder, a mechanical connection between the piston and the breech-block for directly connecting these two elements, a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the end of the barrel, and a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the breech-block, the last passage opening into the barrel nearer to the breechblock than the first passage and being of small cross section relatively to that of the interior of the barrel.

3. An automatic firearm, comprising a fixed barrel, a cylinder, a piston in this cylinder, a mechanical connection between the piston and the breech-block for directly connecting these two elements, a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the end of the barrel, and a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the breech block, the last passage opening into the barrel nearer to the breech-block than the first passage and being of smaller cross-section than that of the first passage.

4. An automatic firearm, comprising a fixed barrel, a cylinder, a piston in this cylinder, a mechanical -connection between the piston and the breech-block for directly connecting these two elements, a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the end of the barrel, a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the breech-block, the last passage opening into the barrel nearer to the breech-block than the first passage and being of smaller cross section than that of the first passage, and a device in the cylinder for directing the gases towards the face of the piston nearest to the breech-block.

5. An automatic firearm, comprising a fixed barrel, a cylinder, a piston in this cylinder, a mechanical connection between the piston and the breech-block for directly connecting these two elements, a passage between s the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearestJ to the end of the barrel, a passage between the barrel and the cylinder for conducting the projectile expelling w gases on the face of the piston nearest to the breech-block, the last passage opening into the barrel nearer to the breech-block than the first passage and being of smaller cross section than that of the first passage, a device in the cylinder for directing the gases towards the face of the piston nearest to the breech-block, and a device in the cylinder for directing the gases towards the opposite face of the piston.

6. An automatic firearm, comprising a fixed barrel, a cylinder, a piston in this cylinder, a mechanical connection between the piston and the breech-block for directly connecting these two elements, a passage between the barrel and the cylinder for conducting the projectile expelling gases on the face of the piston nearest to the end of the barrel, a. passage between the barrel and the cylinder for conducting the projectile expelling gases pn the face of the piston nearest to the breech-block, the last passage opening into the barrel nearer to the breech block than the rst passage and being of smaller cross-section than that of the first passage, a device in the cylinder for directing the gases towards the face of the piston nearest to the breech-block, and an opening in communication with the atmosphere arranged in the wall of the chamber of the cylinder nearest to the breech-block, the said opening being disposed outside of the path of the gases directed towards the piston by the said device.

In testimony whereof I affix my signature.

JOSEPH DESTRE. 

